Offshore oil and gas drilling operations typically include the make-up of strings of pipe or casing members, frequently of relatively large diameter. The tubular strings may be driven into the ground underwater to be used for anchoring the drilling platform or providing the structural foundation of the subsea wellhead system. Such strings are also used as conduits in the water through which a well may be initiated. The joint between members of such tubular strings must provide both structural strength and fluid pressure integrity. Such features of a joint might be provided, for example, by welding. However, because welding is a time-consuming operation, and drilling rig rates are high, particularly offshore, mechanical connectors are generally preferred. Typical mechanical connectors available include the threaded type connectors in which tubular members are mutually rotated to thread a pin and box connector assembly, breach block connectors, and snap lock connectors.
In threaded mechanical connector assemblies an externally threaded end, known as the pin, mates with an internally threaded section, known as the box. The pin and the box on a threaded connector assembly are designed to be engaged with each other and rotated to a specific torque value for connecting the ends. After the connection is made, anti-rotation devices can be installed to secure the pin and the box together at the desired make-up torque. The anti-rotation devices are designed to ensure that the threaded portions of the connector assembly do not become tightened over the desired make-up torque or loosened from each other in response to forces applied to the pipe or casing members in the string.
Existing anti-rotation devices often feature a mechanical key that can be selectively positioned in a recess between the pin and the box of the connector assembly to prevent rotation of the pin and the box relative to each other in a certain direction once the make-up torque is reached. Unfortunately, these keys typically do not go into action to engage with the connector assembly until after the connection is loosened slightly. That is, the keys are generally first positioned in the recesses of the connector assembly, and then the pin and box are rotated slightly relative to each other to energize the key. As a result, the connection may be secured at a different torque than the initial desired make-up torque.
In addition, some existing anti-rotation keys are designed to interface very closely with the connector assembly to fill a recess therein. As such, these keys can be difficult to position in the corresponding recess and often must be hammered into engagement with the connector assembly using a large amount of force. This hammering process takes an undesirable amount of time and energy to ensure that the keys are lodged into their respective recesses in the connector assembly.
U.S. Pat. No. 7,146,704 B2 presents another approach to preventing the first threaded connector from rotating relative to the second threaded connector. However, this approach involves the use of complex boring equipment to form precise holes in the lip of the second connector for receipt of the anti-rotation device and pilot holes for securing the boring equipment into place to form the holes, which receive the anti-rotation device. This approach also requires that a portion of the lip of the first threaded connector be accurately milled out and that upon make-up the milled out section of the first threaded connector be accurately aligned with the hole in the lip of the second connector so that the anti-rotation device can be properly installed. Furthermore, in some embodiments, this solution also requires additional tapping of the holes and milled out sections prior to installation of the anti-rotation device. This approach is thus, a complex, labor-intensive and time-intensive approach to this problem.